Solanum nienkui Merr. & Chun, Sunyatsenia 2: 318. 1935.

Aubriot, Xavier & Knapp, Sandra, 2022, A revision of the " spiny solanums " of Tropical Asia (Solanum, the Leptostemonum Clade, Solanaceae), PhytoKeys 198, pp. 1-270 : 1

29. Solanum nienkui Merr. & Chun, Sunyatsenia 2: 318. 1935.

Fig. 47

Type.

China. Hainan: Sam Ah, 1932, N.K. Chun & C.L. Tso 43319 (holotype: NY [00172269]; isotype: A [00077825]) .

Description.

Erect shrub, to 4 m, unarmed or less often prickly. Stems erect, terete, unarmed or armed with small prickles, sparsely to densely stellate-pubescent, glabrescent; prickles to 3 mm long, to 3 mm wide at the base, curved, deltate, laterally flattened, pale yellow, glabrous; pubescence of mixed sessile and short-stalked porrect-stellate trichomes, the stalks to 0.25 mm long, the rays 4-8, 0.1-0.4 mm long, the midpoints up to 0.8 mm long; new growth densely stellate-pubescent, light brownish to brown in dry material; bark of older stems dark brownish, glabrous. Sympodial units plurifoliate, the leaves not geminate. Leaves simple, not lobed or less often shallowly lobed, the blades 3.5-10.5 cm long, 2.5-4 cm wide, ca. 1.5-2.5 times longer than wide, elliptic to broadly ovate, chartaceous, discolorous, unarmed or sometimes armed with small prickles, the prickles 1-9(-17) per leaf side, mostly inserted on the midvein, like those of the stems; adaxial surface moderately to densely stellate-pubescent, the stellate trichomes porrect, sessile or stalked, the stalks to 0.25 mm long, the rays 3-8, 0.1-0.5 mm long, the midpoints to 0.5 mm long, usually shorter than the rays; abaxial surface densely stellate-pubescent with trichomes like those of the adaxial surface; major veins 4-7 pairs, drying light green; base attenuate to short-attenuate; margins entire, sinuate, sometimes shallowly lobed when young, the lobes 2-3 on each side, 0.3-1 cm long, deltate, apically acute, the sinuses less than halfway to the midrib; apex acute; petioles 1.5-2.5 cm long, 1/7-1/3 of the leaf blade length, unarmed or prickly with 1-7 prickles like those of the stems, densely stellate-pubescent with sessile porrect trichomes like those of the stems. Inflorescences 2.5-7.5 cm long, internodal and lateral or more or less leaf-opposed, unbranched, with ca. 5-13 flowers, 1-3 flowers open at any one time, densely stellate-pubescent, with porrect stellate-trichomes like those of the stems, unarmed; peduncle 0.5-3 cm long, unarmed or armed with 1-3 prickles; pedicels 2.5-10 mm long, ca. 0.5 mm in diameter at the base, 0.75-1 mm in diameter at the apex, recurved, unarmed, densely stellate-pubescent with porrect stellate-trichomes like those of the axes, articulated at the base; pedicel scars spaced 0.1-0.6 mm apart. Buds ellipsoid, tapering, more or less strongly exserted from the calyx before anthesis. Flowers 5-merous, apparently all perfect. Calyx with the tube 1.2-1.5 mm long, campanulate, the lobes 0.5-2.5 mm long, 0.5-1 mm wide, deltate, acute at the apex, unarmed and densely stellate-pubescent with porrect stellate-trichomes like those of the pedicels. Corolla 0.8-1.3 cm in diameter, white to purplish blue, stellate, lobed ca. 4/5 of the way to the base, the lobes 5.5-8 mm long, 1-2.5 mm wide, deltate, spreading at anthesis, densely stellate-pubescent abaxially on parts exposed in bud. Stamens slightly unequal; anthers unequal, two to three of the five 4.5-5.5 mm long and two to three 3.5-4 mm long, all ca. 0.75 mm wide, tapering, connivent, yellow, glabrous, poricidal at the tips, the pores not lengthening to slits with age; filament tube <0.5 mm long, glabrous; free portions of the filaments all equal, ca. 0.1 mm long, glabrous. Ovary conical, minutely glandular-puberulent; style 5.5-6 mm long, slender, curved at the apex, glabrous; stigma capitate, minutely papillate. Fruit a globose berry, 1-4 per infructescence, 0.5-1 cm in diameter, the pericarp smooth, red when mature, glabrous; fruiting pedicels 0.7-1.2 cm long, ca. 0.5 mm in diameter at the base, ca. 2 mm in diameter at the apex, woody, spreading, unarmed; fruiting calyx lobes expanding to 5 mm long, 2/5-3/5 the length of the mature fruit, broadly to narrowly deltate, spreading to perhaps somewhat reflexed, unarmed, ending with a long acumen. Seeds 10-32 per berry, 2.5-3 mm long, ca. 2 mm wide, flattened-reniform, dull yellow, the surface minutely pitted, the testal cells sinuate in outline. Chromosome number: not known.

Distribution

(Fig. 48 ). Solanum nienkui is found on the island of Hainan (South China) and in southern Vietnam.

Ecology and habitat.

Solanum nienkui is found in dry, deciduous forests, growing in more or less open areas on clay or sand, from 100 to 1,000 m elevation.

Common names and uses.

China. shu ci qie ( Zhang et al. 1994); Vietnam. Gia Lai: trong nörvah [Jarai language] (Dournes s.n.); Ninh Thuân: bô kö chinh ao [Mnong language] (Poilane 8933, 20877), dan a xâm [Mnong language] (Poilane 9887), dan chinh ao [Mnong language] (Poilane 9082).

Preliminary conservation status

( IUCN 2019). Near Threatened (LC). EOO (64,999 km2, LC); AOO (72 km2, EN). Solanum nienkui is a plant of dry forests, often considered less valuable than wetter habitats and thus more often subject to anthropogenic change. Given the relatively small areas in which the species occurs and the potential habitat alteration, we have assigned a preliminary status indicating some threat.

Discussion.

Solanum nienkui is a weak shrub with deeply stellate flowers and a slightly zygomorphic androecium. It is morphologically similar to S. robinsonii and S. putii , and in the molecular analyses of Aubriot et al. (2016a) resolved as sister to S. putii in a group with S. camranhense that itself was sister to S. cyanocarphium . It differs from S. robinsonii (also found in Vietnam) in its wider, less discolorous leaves, deeply stellate, smaller corolla, and somewhat zygomorphic androecium. Solanum camranhense has similar shaped leaves to those of S. nienkui but is a low creeping plant rather than an upright, spindly shrub.

Specimens examined.

See Suppl. materials 1-3.

Figures

Figure 47. Solanum nienkui Merr. & Chun A herbarium specimen collected in Vietnam in 1932 (Poilane 20877, P 00054081) B inflorescence and young stem (Wang et al. 2073, China) C detail view of a flower (Wang et al. 2073, China). Photograph credits: A CC-BY, Museum national d'Histoire naturelle, Paris B, C S. Hul.

Figure 48. Distribution of S. nienkui.